Brake for hoisting-drums



- (No ModeL) Y W. C. DAVIS.

\ BRAKE FOR HOISTING DRUMS. 'No.'466,158. "Patented Dec. 29, 1891.

! at H v Ew ilZZZiam 6.1720/6' UMTED STATES P TENT OFFICE.

lVILLlAM O. DAVIS, OF DENVER, COLORADO.

BRAKE FOR HOlSTlNG-DRUMSf SPECIFICATION forming part of Letters PatentNo. 466,158, dated December 29, 1891.

' Application filed June 10,1891. Serial No. 395,795. (No model.)

To all whom it may concern.-

Be it known that 1, WILLIAM C. DAVIS, a citizen of the United States ofAmerica, residing at Denver, in the county of Arapahoe and State ofColorado, have invented certain new and useful Improvements in Brakesfor Hoisting-Drums, of which the following is a specification.

My invention relates to an automatic safetybrake which is speciallydesigned to be used in connection with a hoisting-drum, though I do notdesire to limit myself in this connection, as the invention may beapplied with equally good effect in other situations without departingfrom the spirit of my invention.

In the accompanying drawings I have represented my invention inconnection with the form of drum patented to F. M. Davis on the 11th ofDecember, 1888, No. 304,344, for the sake of convenience.

In the drawings, Figure 1 represents a side elevation of the drum withmy present improvement attached thereto, and Fig. 2 is a rear view ofthe same.

J represents the winding-drum, which in the longitudinal movement of thesliding shaft is adapted to engage the friction-ring, and on theapplication of power to said ring the drum may be moved therewith. Thisdrum is provided with an extension M, which is adapted for the action ofmy improved brake-band. This band is shown at F, and is a fiat piece ofmetal, which passes around the extension of the drum and is secured .atone end by passing around a bolt supported in projecting ears 0, whichform, practically, the short arm of a bell-crank lever pivoted at B, thelong arm of which is shown at A and extends upward and outward from itspivot, the extreme upper end of this long arm being Weighted, as at G.The other end of the band is connected to the long arm of the bellcrankby means of a pivoted screw g, which provides adjustment for the strap,so that it may be lengthened or shortened according to the situation ofthe band.

In Fig. 2 I have indicated by the arrow K the direction in which thedrum turns in hoisting, and by the arrow L the direction in which thedrum turns in lowering.

hen the drum is being hoisted, turning in the direction of the arrow K,the pull, through frictional contact with the band F, is on the long armof the bell-crank lever, which has the efiect of loosening the band, andthus the drum is free from the binding effect of the band. As soon,however, as the hoisting stops and the Weight of the load starts thedrum in the direction of the arrow L, the drum having been released fromthe frictional clutch, the friction on the band F is transmitted to theshort arm of the bellcrank at 0, drawing it in to the right, as in Fig.'

2, and the further movement of the short arm is sufficient to give muchgreater movement to thelong arm, which has the effect of cansing theband F to grip the surface of the on tension M, and thus the movement ofthe drum will be retarded. The action is entirely automatic, and it isonly necessary to make the arms of the bell-crank of proper length toget any desired force in the action of the parts.

For moving the drum longitudinallyin order to engage and disengage thefriction-disk 00 an arm 0 is used, which is operated by a lever Y and alink .2, Fig. 2. The arm is connected to the screw-threaded sleeve 2,-and when moved to the left it causes the screwsleeve to move the druminto engagement with the friction-disk, and when moved to the right thedrum is disengaged by the same means. The arm is shown in Fig. 2 asmoved to the right far enough to disengage the drum from thefriction-disk, and the load being now raised the drum is held againstbackward movement by the automatic action of the brake-band and itscrank-lever.

In order to release the band to permit th drum to unwind, the arm 0 iscapable of further movement to the right by means of the hand-lever, andin this movement a shoulder E on the arm bears against the extension Nof an 'arm D and presses it down. This arm is connected with thebell-crank lever and turns the same, so as to raise the longer armthereof, and thus release the brake-band. When the load is again hoistedand the brakeband automatically operated upon the release of the drumfrom the friction-disk, the turning of the bell-crank lever raises thearm D, so that its'extension will be in position to be pressed down bythe arm 0 when the said arm is moved to its extreme position to theright.

In other styles of hoistinganachines a separate hand or foot lever maybe connected to the arm D or to the short arm 0 of the bellcrank torelease the drum from the clutch of the band.

I claim as my invention- 1. In combination, the friction-disk, the drum,the hand-lever, and connecting devices for operating the drumlongitudinally to engage and disengage the friction disk, the brake-bandhaving its ends connected by a lever with a long and short arm, saidband and lever being capable of automatic operation when the handleverand connections are partially operated to disengage the drum, and aloose connection from the brake-band lever to the drum-operatingdevices, whereby the brake-band may be released by the full movement ofthe hand-lever, substantially as described.

2. In combination, the friction-disk with operating means therefor, adrum with means for moving it longitudinally to engage and disengage thesaid disk, the extension on the drum, the brake -band adapted to engagetherewith, the bell-crank lever having its arms connected to the ends ofthe brake-band, and the arm D, connected to the bell-crank lever, thesaid arm extending into position to be operated by the drum-shiftingmeans when the same is moved to disengage the drum from thefriction-disk, substantially as described.

In combination, the friction-disk with operating means therefora drum,the shaft therefor, the means for shifting the drum to engage anddisengage the friction-disk, consisting of the screw-threaded sleeve,the arm 0, and the means for operating the arm, the drum-extension, thebrake-band therefor, the leverconnected to the ends of the brake-band,and the arm D, connected with the lever and extending to the arm 0 to beoperated thereby, substantially as described.

In testimony whereof I affix my signature in presence of two Witnesses.

IVILLIAM (I. DAVIS.

\Vitnesses:

A. W. KING, A. W. HILLE.

